1. Field of the Invention
The present invention relates generally to a isolated forward mode DC-DC converter.
2. Description of the Related Art
DC to DC converters are known which use primary and secondary control methods. Primary control methods use opto couplers to provide isolation between the input and the output though an analog control path. Secondary control methods typically use isolated drive transformers. A DC blocking capacitor is typically used in series with the driver transformer in such converters to prevent saturation. Since for a wide range converter, the duty cycle can vary from three or four to one, the drive voltage from the transformer can also vary in amplitude by that amount. This is due to the DC blocking capacitor. At high duty cycles, there may not be enough drive voltage, while at low duty cycles, there may be too much. Also, the transformer size is determined by the actual switching frequency.